A technique has been disclosed (see Japanese Patent Application Publication No. 2011-240779, for example) in which a perception mark for allowing the driver to perceive the positional relation between the position of the driver and the center in the vehicle width direction, to support driving of the vehicle without obstructing the driver's view is provided, in a position shifted upward for a predetermined height from a frame portion extending the circumferential edge of a front window.
However, the technique described in Japanese Patent Application Publication No. 2011-240779 does not facilitate spacing between vehicles in the right-left direction. Also, in the technique described in Japanese Patent Application Publication No. 2011-240779, the perception mark is provided in a position away from the frame portion of the front windshield, and therefore may be mistaken as dust or other objects attached to the front windshield.